Electrohydrodynamic 3D printing of microscale poly (ε-caprolactone) scaffolds with multi-walled carbon nanotubes

Electrohydrodynamic 3D printing is a promising strategy to controllably fabricate hierarchical fibrous architectures that mimic the structural organizations of native extracellular matrix. However, most of the existing investigations are mainly based on viscous melted biopolymers which make it difficult to uniformly incorporate bioactive or functional nanobiomaterials into the printed microfibers for functionization. Here we investigated the feasibility of employing solution-based electrohydrodynamic 3D printing to fabricate microscale poly (ε-caprolactone) (PCL) scaffolds with multi-walled carbon nanotubes (MWCNTs). The effect of polyethylene oxide (PEO) content in the acetic acid solution of PCL on the 3D profile and dimension of the electrohydrodynamically printed walls was studied for an optimal PEO-PCL composition. When the contents of PEO and PCL are 8 w/v % and 5 w/v %, respectively, 3D fibrous lactic structures with different MWCNTs content could be stably printed with the fiber diameter about 10 μm, close to the size of living cells. Biological experiments showed that although the addition of MWCNTs negatively affected cellular attachment compared with PEO-PCL scaffolds, the electrohydrodynamically printed PEO-PCL-MWCNT scaffolds facilitated cell alignment. It is envisioned that the presented electrohydrodynamic 3D printing might provide a new strategy to flexibly incorporate various nanobiomaterials into microscale fibrous structures for specific functionality or mimicking of hierarchically organized nanocomposites in vivo.